Single-crystal X-ray Diffraction Research Articles

Solvent and additive-controlled supramolecular isomerism in zinc coordination polymers

AbstractA new series of Zn(II) supramolecular isomers containing ditopic 1,3-di(pyridin-4-yl)urea (4bpu) ligand were synthesized and characterized by infrared analysis, elemental analysis and TGA as well as single-crystal X-ray diffraction analysis. Four solvent-induced pseudopolymorphic zinc (II) coordination polymers (CPs), namely, {[Zn(4bpu)(OAc)2](CH3OH)}n (1), {[Zn(4bpu)(OAc)2](C2H5OH)}n (2), {[Zn(4bpu)(OAc)2](HOCH2CH2OH)}n (3), and {[Zn(4bpu)(OAc)2](0.5H2O)}n (4), were prepared by the reaction of Zn(OAc)2.2H2O and 4bpu via self-assembly under varying solvent systems. Also, a pair of polymorphic coordination polymers namely, {[Zn(4bpu)(OAc)2](CH3OH)}n (1α) and {[Zn3(4bpu)3(OAc)6](CH3OH)2}n(1β), was prepared in the presence of different organic additives. Single-crystal X-ray diffraction confirmed that 1−4 and 1α display 1D polymeric zig-zag chains and 1β exhibits 1D triple-stranded ladders that were self-assembled through various supramolecular interactions. In addition, a series of dissolution-recrystallization structural transformations (DRST) were performed on these supramolecular isomers.

HOST‐GUEST INTERACTIONS FACILITATED BY CHALCOGEN BONDING WITHIN SELENADIAZOLE FUNCTIONALISED PORPHYRIN NANOTUBES

The structural rigidity of tetrakis(4‐pyridyl)porphyrin (TPyP) has been utilised to prepare a robust novel porous coordination polymer of composition Cd2(TPyP)(sez)2 (TPyP = 5,10,15,20‐tetra(4‐pyridyl)porphyrin, sez = 1,2,5‐benzoselenadiazole‐5‐carboxylate). The coordination polymer may be described as a hexagonal porphyrin nanotube (PNT) and has the potential to bind guest molecules through chalcogen bonding. Single crystal X‐ray diffraction (SCXRD) data indicate an internal pore diameter ~9 Å which represents ~35% of the crystal volume. Immersion of the PNTs in solvents such as DMSO and CS2 result in the incorporation of these molecules within the nanotubes with chalcogen bonding between host and guest. The crystallographic guest‐inclusion investigations are complemented by solid‐state 77Se, 13C, 113Cd and 2H NMR studies which provide insights into dynamic behaviour. The porosity of the crystals was further explored using gas adsorption experiments, indicating the reversible uptake of CO2, CH4, H2 and N2. Structure‐function relationships are clearly established from complementary crystallographic, NMR and adsorption investigations.

Crystal structure of AlPCl8

The crystal structure of aluminium phosphorus chloride (systematic name: phosphorus tetrachloride tetrachloridoaluminate), (PCl4)[AlCl4] or AlPCl8, was determined and refined using single-crystal X-ray diffraction data. The compound crystallizes in the orthorhombic space group Pbcm. The asymmetric unit comprises one Al atom, one P atom, and five Cl atoms. The structure is characterized by isolated AlCl4 and PCl4 tetrahedra, isostructural with FePCl8 and GaPCl8.

Syntheses, structures and characterization of noncentrosymmetric MZnPO4 (M = K, NH4).

Two phosphates, KZnPO4 and NH4ZnPO4, were successfully synthesized using a solid-state reaction method and characterized via single-crystal X-ray diffraction. Both of their structures feature a three-way skeleton composed of isolated PO4 and ZnO4 tetrahedra, with K+/NH4+ cations occupying the spaces within the frameworks to balance charges. These compounds are isostructural and crystallize in the noncentrosymmetric P63 space group. Their structures were compared, revealing that non-centrosymmetric (NCS) KZnPO4 and NH4ZnPO4 exhibit second harmonic generation (SHG) responses of 0.4 × KDP and 1 × KDP, respectively. Furthermore, by combining the electronic structure and SHG density calculations, we examined the effects of ZnO4 tetrahedra on the SHG response of KZnPO4 and NH4ZnPO4.

Synthesis, Crystal Structure, Spectroscopic Characterization, In Vitro and In Silico Molecular Docking Studies of Benzyl Tetrazole-N-Isobutyl Acetamide Hybrid

Background: Tetrazole-based compounds are of significant interest due to their potential pharmacological applications. The current study focuses on the synthesis and analysis of such a compound. Objective: This research aims to synthesize the title compound N-(3-methyl-1-phenyl-2-(1Htetrazol- 1-yl) butyl) acetamide, analyze its crystal structure, perform computational studies, and evaluate its potential pharmacological activities and it’s in silico and in vitro supports, specifically antidiabetic and anti-inflammatory properties. Methods: The title compound, C14H19N5O, was synthesized, and its crystal structure was confirmed using single-crystal X-ray diffraction analysis by default parameters. Density Functional Theory (DFT) calculations were performed using the Gaussian 09W software package with the B3LYP/6-311++G (d,p) method to optimize the compound's structure and calculate its HOMOLUMO energy gap, Molecular Electrostatic Potential (MEP), and Mulliken charge distribution. In vitro, antidiabetic and anti-inflammatory activities were assessed and compared with standard drugs by using reported protocols. Additionally, molecular docking studies were conducted with enzymes related to diabetes and inflammation with default parameters, and Auto-Dock 4.2 software was used. Results: The X-ray diffraction analysis confirmed the crystal structure, and the Density Functional Theory (DFT) calculations provided insights into the molecular properties of the compound. Molecular docking experiments with relevant enzymes further supported the significant antidiabetic and anti-inflammatory activities demonstrated in the in vitro tests. Conclusion: The synthesized tetrazole-based compound exhibits promising antidiabetic and antiinflammatory activities, supported by both experimental and theoretical studies, suggesting its potential for further pharmacological investigation.

Cs3LiGe4, One Compound with Two Complementary Structural Descriptions: Isolated [Ge4]4- Tetrahedral Clusters Coordinated by Li+ and Cs+ Cations or One-Dimensional [LiGe4]3- Polyanions Packed within a Matrix of Cs+ Cations?

Reported are the synthesis and structural characterization of Cs3LiGe4, the first structurally characterized lithium-containing cesium germanide. Single-crystal X-ray diffraction data indicate that Cs3LiGe4 crystallizes in an orthorhombic crystal system with the space group Cmcm (no. 63, Person symbol oS32) with unit cell parameters a = 6.950(2) Å, b = 15.503(3) Å, and c = 9.919(2) Å and V = 1068.65(4) Å3. The structure consists of [Ge]44- tetrahedral clusters with the Li atoms positioned in such a way that polyanionic [LiGe]43- chains could be considered as well. Electronic structure calculations indicate an intrinsic semiconductor with a band gap of 0.76 eV. To understand the nuances of the chemical bonding, position-space techniques based on the quantum theory of atoms in molecules, the electron localizability indicator, and their basin intersections were employed confirming the covalent character of the Ge-Ge bonding. The strong polarity of the interactions between [Ge]44- and the surrounding lithium and cesium cations suggests to interpret these as mainly ionic, further supporting the most basic structure rationalization [Cs+]3[Li+][Ge]44-, following the Zintl-Klemm concept. The electron localizability indicator topology affirms the striking similarities between [Ge]44- and molecular As4 tetrahedra in yellow arsenic, further supporting Klemm's pseudoatom concept on a quantum chemical basis.

Rational Design of Crystalline and Enantiomerically Pure Helicenes with Open-Shell Singlet Ground States.

Helicene diradical derivatives have attracted widespread attentions because of their unique magnetic and chiroptoelectronic properties, however, crystalline and enantiomerically pure forms of helicene diradicals are extremely rare. Herein, we describe the rational design and synthesis of o-quinone functionalized helicene diradicals with crystalline enantiomerical purity. Diradical dianion salt Rac-3K and its enantiomers P/M-3K were obtained by reduction of corresponding precursors Rac-3 and P/M-3 with two equivalent potassium graphite in THF in the presence of (di)benzo-18-crown-6. Neutral dioxoborocyclic helicene diradicals (Rac-3B and P/M-3B) were produced by reactions of Rac-3 or P/M-3 with chlorobis(perfluorophenyl)borane (B(C6F5)2Cl. Crystal structures of compounds Rac-3K, Rac-3B and P/M-3K were obtained by single crystal X-ray diffraction. Their open-shell singlet state ground states were confirmed by electron paramagnetic resonance (EPR) spectroscopy, superconducting quantum interference device (SQUID) measurements and theoretical calculations. Their chiroptical properties were investigated by the electronic circular dichroism (ECD) spectroscopy. This work provides the first examples of enantiopure helicene diradical dianions and boron-containing helicene diradicals.

Osmaborane Clusters with B4 and B5 Rings Stabilized in the Coordination Sphere of {OsLn} (Ln = η5-C5Me5 or H2(PPh3)2).

New synthetic routes have been developed to synthesize osmaborane clusters featuring B4 and B5 rings in the coordination spheres of osmium. Thermolysis of [Os(PPh3)3Cl2], 1 in the presence of excess of [BH3·THF] led to the formation of [Os(PPh3)2H2(η4-B4H8)], 2 along with [HOs(PPh3)2B5H10], 3. Cluster 2 features a planar tetraborane ring coordinated to an osmium center in an η4 fashion. Cluster 3 can be considered an osmium analogue of hexaborane(10), in which the osmium center is situated at the base of the pentagonal pyramid geometry. In a different synthetic protocol, we have carried out the metathesis reaction of [Cp*OsBr2]2 (Cp* = η5-pentamethylcyclopentadienyl), 5 with [LiBH4·THF] followed by thermolysis in the presence of [BH3·THF] that generated [Cp*Os(η5-B5H10)], 6. Cluster 6 has a planar pentaborane ring that is stabilized in the coordination sphere of osmium, making it a boron analogue of osmocene. Clusters 2 and 6 are the first examples of structurally characterized planar B4 and B5 rings, respectively, that are stabilized in the coordination sphere of osmium. All the synthesized molecules were characterized using multinuclear NMR and IR spectroscopy, mass spectrometry, and single crystal X-ray diffraction analyses. Theoretical calculations were carried out to visualize the electronic structures and bonding scenarios in 2 and 6.

Synthesis and Characterization of Lithium Pyrocarbonate (Li2[C2O5]) and Lithium Hydrogen Pyrocarbonate (Li[HC2O5]).

The anhydrous pyrocarbonate and the first hydrogen pyrocarbonate Li[HC2O5] have been synthesized in a laser-heated diamond anvil cell at moderate pressures ( GPa). The structures of the two compounds have been obtained from single crystal X-ray diffraction data. Raman spectroscopy and DFT calculations have been employed to further characterize their structure-property relations. The present results significantly enlarge the group of inorganic pyrocarbonates by the discovery of the hydrogenated pyrocarbonate anion Li[HC2O5]-. In the structure of Li[HC2O5] there is a symmetric O-H-O arrangement at high pressures, which converts to a conventional O-H O hydrogen bond upon pressure release.

Three new members of the hakite series, Cu6(Cu4Me2+2)Sb4Se13: hakite-(Cd), hakite-(Fe) and hakite-(Zn) from the Bytíz deposit, uranium and base-metal Příbram ore district, Czech Republic

Abstract Hakite-(Cd), hakite-(Fe) and hakite-(Zn) are new minerals belonging to the tetrahedrite group and forming, along with hakite-(Hg), the hakite series. They have been discovered in samples collected from the Bytíz deposit, in the uranium and base-metal Příbram ore district, Central Bohemia, Czech Republic. They occur as anhedral grains, up to 300 μm in size, in a calcite gangue, associated with clausthalite, cadmoselite, hakite-(Hg) [for hakite-(Cd)], berzelianite, bukovite, bytízite, crookesite, chaméanite, eskebornite, příbramite, the not yet approved giraudite-(Hg) and giraudite-(Cu), hakite-(Hg), umangite, chalcopyrite, tetrahedrite-(Zn) and a new Cu–As selenide [for hakite-(Fe) and -(Zn)]. The three new species are black, with a metallic lustre. Mohs hardness is ca. 3½–4; calculated density is 6.019 (Hak-Cd), 6.011 (Hak-Fe) and 6.081 g.cm–3 (Hak-Zn). In reflected light, they are isotropic, pale grey with bluish (Hak-Cd) or brownish (Hak-Fe and Hak-Zn) shades. Empirical formulae of hakite-(Cd), hakite-(Fe), and hakite-(Zn) are Cu9.71Ag0.24Cd1.51Hg0.43Zn0.03(Sb3.94As0.13)Σ4.07Se11.35S1.57, Cu10.11Ag0.18Fe0.81Zn0.50Hg0.26(Sb3.72As0.41)Σ4.13Se12.65S0.12, and Cu10.03Ag0.24Zn0.61Fe0.53Hg0.45(Sb3.55As0.60)Σ4.15Se12.82S0.08, respectively. These formulae correspond to the end-member formulae Cu6(Cu4Cd2)Sb4Se13 (Hak-Cd), Cu6(Cu4Fe2)Sb4Se13 (Hak-Fe), and Cu6(Cu4Zn2)Sb4Se13 (Hak-Zn). All these new members of the hakite series are cubic, I $\bar{4}$ 3m, Z = 2, with unit-cell parameters a = 10.8860(6) Å, V = 1290.0(2) Å3 (Hak-Cd); a = 10.7983(4) Å, V = 1259.12(14) Å3 (Hak-Fe); and a = 10.8116(14) Å, V = 1263.8(5) Å3 (Hak-Zn). These species are isotypic with the other members of the tetrahedrite group, and their crystal structures have been refined on the basis of single-crystal X-ray diffraction data down to R1 values of 0.0230 (Hak-Cd), 0.0254 (Hak-Fe), and 0.0302 (Hak-Zn). These structural data allow us to describe the S-to-Se partitioning in hakite-series minerals and to understand the mechanisms avoiding too short Me–Se distances in these selenides.

Enzyme (α-Glucosidase, α-Amylase, PTP1B & VEGFR-2) Inhibition and Cytotoxicity of Fluorinated Benzenesulfonic Ester Derivatives of the 5-Substituted 2-Hydroxy-3-nitroacetophenones

The prevalence of small multi-target drugs containing a fluorinated aromatic moiety among approved drugs in the market is due to the unique properties of this halogen atom. With the aim to develop potent antidiabetic agents, a series of phenylsulfonic esters based on the conjugation of the 5-substituted 2-hydroxy-3-nitroacetophenones 1a–d with phenylsulfonyl chloride derivatives substituted with a fluorine atom or fluorine-containing (-CF3 or -OCF3) group were prepared. Their structures were characterized using a combination of spectroscopic techniques complemented with a single-crystal X-ray diffraction (XRD) analysis on a representative example. The compounds were, in turn, assayed for inhibitory effect against α-glucosidase, α-amylase, protein tyrosine phosphatase 1 B (PTP1B) and the vascular endothelial growth factor receptor-2 (VEGFR-2) all of which are associated with the pathogenesis and progression of type 2 diabetes mellitus (T2DM). The antigrowth effect of selected compounds was evaluated on the human breast (MCF-7) and lung (A549) cancer cell lines. The compounds were also evaluated for cytotoxicity against the African Green Monkey kidney (Vero) cell line. The results of an in vitro enzymatic study were augmented by molecular docking (in silico) analysis. Their ADME (absorption, distribution, metabolism and excretion) properties have been evaluated on the most active compounds against α-glucosidase and/or α-amylase to predict their drug likeness.

Small Molecule Activation by 4‐N,N‐Dimethylaminopyridine‐Stabilized Bis(silyl)germylenes

AbstractThe synthesis, characterization, and reactivity of DMAP⋅Ge(SitBu3)Si(TMS)3 1 a and DMAP⋅Ge[Si(TMS)3]2 1 b are reported (DMAP = 4‐N,N‐Dimethylaminopyridine). These germylenes were isolated in moderate yields by the reaction of DMAP⋅GeCl2 with NaSitBu3⋅(THF)2 and KSi(TMS)3⋅(THF)1.2 or 2 equivalents of KSi(TMS)3⋅(THF)1.2, respectively, at low temperature (TMS = Trimethylsilyl). Exposure of 1 a to dihydrogen forms the tetravalent germanium hydride species GeH2(SitBu3)Si(TMS)3 2 a. Additionally, the reactivity of 1 a,b towards the substitution of 2,6‐dimethylphenyl isocyanide (CNXyl) 3 a,b, the alkyne cycloaddition of diphenylacetylene (PhCCPh) 4 a,b, and the substitution of DMAP for NHC using 1,3,4,5‐tetramethylimidazol‐2‐ylidene (IMe4) 5 a,b was investigated (NHC = N‐heterocyclic carbene). Reaction products were characterized by multinuclear magnetic resonance (NMR), infrared (IR) spectroscopy, mass spectrometric analysis, and single‐crystal X‐ray diffraction (SC‐XRD) study.

Double‐Walled Honeycomb‐Like Metal‐Organophosphonium Framework with High H2 Gas Adsorption Capacities

AbstractThis study successfully synthesized a new Metal‐Organic Framework (MOF) named CJLU−L2, which was constructed from phosphorus‐containing ligands and Co(II) ions. The structure revealed through single‐crystal X‐ray diffraction (SCXRD), features a double‐walled honeycomb‐shaped structure with a one‐dimensional channel of ~6.5 Å. According to the PLATON calculation, the pore volume per unit cell of CJLU−L2 was determined to be 6825.0 Å3, constituting 57.5 % of the total crystal volume (11874.9 Å3). The Brunauer‐Emmett‐Teller (BET) surface area of CJLU−L2 was determined to be 954 m2/g by N2 adsorption measurement at 77 K. The phase purity of CJLU−L2 was verified by powder X‐ray diffraction (PXRD) and infrared spectroscopy (IR), while its thermal stability was confirmed by thermogravimetric analysis (TGA). Hydrogen adsorption experiments demonstrate that CJLU−L2 exhibits a high hydrogen adsorption capacity, indicating significant potential for gas adsorption applications.

Bismuth Bound to Transition Metals: Visible-Light-Induced Olefin Coordination, Reductive Elimination, and Oxidative Addition.

A series of dibenzobismepinyl (C14H10Bi) substituted transition metal complexes of the type [(C14H10Bi)M(CO)x(L)] (M = Mn, Co, Fe) was prepared in salt elimination reactions from a halobismepine and sodium metallates. Irradiation of these complexes with visible light has been investigated, aiming at the elimination of one carbonyl ligand and the concomitant coordination of the bismepine's olefin moiety to the transition metal center. The resulting complexes of the type [{κ2C,κ1Bi-(C14H10)Bi}M(CO)x-1(L)] (M = Co, Fe) have been isolated and fully characterized. When two dibenzobismepinyl units are positioned in the coordination sphere of an iron carbonyl complex fragment, reductive elimination / oxidative addition events of the dibismuthane (C14H10Bi)2 have been shown to be relevant. The analytical techniques applied in this work include (heteronuclear) NMR spectroscopy, elemental analysis, single-crystal X-ray diffraction analysis, UV/Vis spectroscopy, IR spectroscopy and (TD)-DFT calculations.

Impurities in Arylboronic Esters Induce Persistent Afterglow.

Several recent reports suggest that arylboronic esters can exhibit room temperature phosphorescence (RTP), an optical property that is desirable for applications in security printing, oxygen sensing, and bioimaging. These findings challenged the fundamental notion that heavy elements or changes in orbital symmetry were required for intersystem crossing to occur in organic compounds. As we had not observed long afterglow in the many arylboronic esters we had synthesized over many years, we suspected that the RTP observed in these systems had a simpler explanation: the materials reported were impure. Herein, we synthesized 12 arylboronic esters that were previously reported to show RTP, and carefully purified them by column chromatography, recrystallization, and sublimation. We re-examined their photophysical properties alongside single-crystal X-ray diffraction analysis and detailed theoretical studies. While 4 of the 12 compounds showed long afterglows as crude products, none of them showed persistent RTP after careful purification. We also successfully isolated the impurity 4-amino-3,5-bis(pinacolatoboryl)benzonitrile (2), identifying it as the impurity responsible for inducing delayed fluorescence in 3,5-bis(pinacolatoboryl)benzonitrile (1). Doping 1 with 1.0 mol % 2 led to a persistent afterglow with a lifetime of 67 ms, which is mediated by a dimer charge transfer state. Our findings call for a re-examination of previous studies reporting RTP from arylboronic esters, highlight the importance of careful purification in photophysical research, and provide a practical strategy for designing organic materials with a long afterglow.

Structurally Diverse Duclauxins from a Coral-Derived Talaromyces sp. and Insight into Determining the Configuration at C-1 of Heptacyclic Duclauxins by 1H NMR.

A chemical investigation of the coral-derived fungus Talaromyces sp. TJ403-AL05 led to the isolation of 18 duclauxin analogues (1-18), 14 of which, taladuxins A-N (1-14), are new and consist of the first example of duclauxin fused with one 1,6-dioxaspiro[4.5]decan-2-one moiety (1), as well as its biosynthetic product (2), and 12 6/6/6/5/6/6/6 heptacyclic derivatives (3-14). Comprehensive spectroscopic analyses, electronic circular dichroism (ECD) calculations, DP4+ probability analyses, single-crystal X-ray diffraction, and vibrational circular dichroism (VCD) calculations were employed to characterize their structures and revise the published structure of verruculosin B. An efficient 1H NMR method was established to discriminate 1R and 1S configurations at C-1 of 6/6/6/5/6/6/6 heptacyclic duclauxins according to chemical shift differences of diastereotopic methylene H2-11 or H2-12 (ΔδH-11 or ΔδH-12). Compounds 4, 7-8, 13-15, and 18 exhibited moderate inhibition of Arabidopsis thaliana 4-hydroxyphenylpyruvate dioxygenase (AtHPPD), with IC50 values ranging from 17.1 to 71.3 μM.

Coordination Modes of Ortho-Substituted Benzoates Towards Divalent Copper Centres in the Presence of Diimines

The coordination modes of several ortho-substituted benzoates towards the copper(II) centre are investigated. The coordination environment of the metal ion includes nitrogen atoms from 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen) and occasionally oxygen atoms from coordinated water, ethanol molecules, or nitrate ions. The compounds are investigated by a variety of spectroscopic methods and by single-crystal X-ray diffraction. Although the reaction scheme involved equimolar amounts of the reactants, cationic dinuclear compounds with a metal/benzoate/diimine ratio of 2:3:2 have been realized, cationic in nature regardless of the counter anion used. Furthermore, the carboxylate moieties display a range of twisting relative to the orientation of the benzene ring to which they are attached.

A d10-Cd Cluster Containing Sandwich-Type Arsenotungstate Exhibiting Fluorescent Recognition of Carcinogenic Dye in Methanol

A d10-Cd cluster containing sandwich-type arsenotungstate [C3H12N2]6[Cd4Cl2(B-α-AsW9O34)2] was synthesized and its structure characterized through elemental analyses, X-ray powder diffraction (XRPD), IR spectroscopy, X-ray photoelectron spectroscopy (XPS), and single-crystal X-ray diffraction. The X-ray analysis revealed that the molecular unit of the compound consists of a captivating tetra-Cd-substituted sandwich-type polyoxoanion, accompanied by six elegantly protonated 1,2-diaminopropane as counter ions. The further novelty of the tetranuclear cadmium cluster lies in its occupied chlorine atom sites. This makes it highly susceptible to coordinate reactions with nitrogen on polycyclic aromatic hydrocarbons, thereby exhibiting different fluorescent signals that facilitate the identification and detection of these carcinogenic substances in methanol.

A methodical investigation on stilbazolium derivative substituted with 2,4-Dichlorobenzaldehyde as a donor: An effective crystal for optical device fabrication

For a couple of decades, nonlinear optics (NLO) has garnered significant attention due to its widespread application in optical systems. In this viewpoint, a new 2-[2(2,4-Dichloro-phenyl)vinyl]methyl-1-pyridinium iodide (DCPI) crystal was grown through slow evaporation process for NLO application. Single Crystal X-ray diffraction (SCXRD) study reveals that the DCPI crystallized centrosymmetric (P-1) space group. The CHN elemental analysis and NMR spectroscopy assess the purity of the material. The vinyl (CC) group formation in DCPI was asserted by the Fourier-transform infrared (FT-IR) spectrum. The Hirshfeld surface analysis confirms the presence of hydrogen bonds in the crystal structure through its contribution percentage (27 %) to the overall intermolecular interaction. DCPI crystal exhibits 80 % transparency in the visible region. Luminescence studies assess the green light-emitting characteristics of the DCPI crystal. The etching and Atomic Force Microscopy (AFM) studies confirm that the DCPI crystal has a flat surface with minimum dislocations. Z-scan studies found the third-order nonlinear characteristics of the crystal. Overall, the article illustrates the appropriateness of DCPI crystal in fabricating optical devices through its significant optical characteristics.

Thuwalamides A–E: polychlorinated amides from the marine sponge Lamellodysidea herbacea collected from the Saudi Arabian Red Sea

Thuwalamides A–E (1, 3, 5, 6 and 8), previously undescribed polychlorinated amides, along with ten previously reported related compounds (2, 4, 7 and 9–15), were isolated from the organic extract of the marine sponge Lamellodysidea herbacea (Keller), collected off the village of Thuwal in the Red Sea at Saudi Arabia. The structures of the isolated compounds have been determined through extensive analysis of their NMR and MS data, while their absolute stereochemistry was unequivocally established via single crystal X-ray diffraction. Additionally, the absolute stereochemistry of the previously reported compounds 2 and 4, whose configuration was not determined, has also been established using single-crystal X-ray crystallographic analysis. The antibacterial activity of compounds 1–15 was evaluated against Escherichia coli and Staphylococcus aureus. Among them, compound 14 displayed activity against S. aureus comparable to vancomycin that was used as a positive control with a MIC value of 4 μg/mL.